On 08/03/2010, at 12:17, Alexander Solla wrote:
>> GHC even optimizes it to:
>>
>> fib = fib
>
> Sounds like an implementation bug, not an infinite dimensional vector space
> bug. My guess is that strictness is getting in the way, and forcing what
> would be a lazy call to fib in the corresponding list code -- fib = 0 : 1 :
> (zipWith (+) fib (tail fib)) -- into a strict one.
>
> In fact, I'm pretty sure that's what the problem is:
>
> data Vector a = Vector {-# UNPACK #-} !Int
> {-# UNPACK #-} !Int
> {-# UNPACK #-} !(Array a)
The problem is that you have to allocate an Array of a specific length when
creating a Vector. Arrays are finite by definition. It's not a bug, it's a
feature.
Note that in the context of package vector, "vector" means a 1-dimensional,
0-indexed array. This is not unusual - see, for instance, the standard C++
library.
Roman
_______________________________________________
Haskell-Cafe mailing list
Haskell-Cafe@haskell.org
http://www.haskell.org/mailman/listinfo/haskell-cafe
